Transformer.



0. LE G. PORTESOUE.

TRANSFORMER. APPLIOATION FILED NOV. 19, 1908. RENEWEDJUNE 15, 1911. 1,01 3,150.

' Patented Jan. .2, 1912. I

2 SHBE TS-SHEET 1.

AT'TORNEY 0; LE G. PORTBSGUE L TRANSFORMER.-

APPLIOATION FILED NOV. 19, 1 908. RENEWED JUNE i5, 1911.

2 SHEETS-SHEET 2.

nil,

WITNESSES:

' INVENTOR w floimn Patented J mi. 2, 1912.

urnn srnrss CHARLES LE G. FORTESCUE, OF VJILKINSBUIRG, ?ENN$YLVANIA ASSIGNOR TC) WEST- INGHOUSE ELECTRIC 8; MANUFACTURING COMFANY, A CORPQRATIDN 0F PENN- SYLVANIA.

rnansromvinn.

Patented Jan, 2, 1912.

Application filed November 19, 1908, Serial No. 463,486: Renewed June 15, 1911. Serial No. 633,348.

To all whom it may 0012mm:

, Be it known that I, CHnnLns Li: G. Fonrnsocs, a subject of the King of Great Britain, and a residentof l/Vilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in, Transformers, of which the following is a specification.

. My invention relates to stationary inductive apparatus, and it has for object to provide an improved transformercore structure, by the use of which the expenses of operation and the losses in the transformer may be reduced." v

In order to'reduce the mean length of turn in the transformer windings, it has been found desirable to reduce the crosssectional area oi the portions of the-core structure which are disposed within the coils. The flux density of the portions having the reduced section is, of course, increased, and it is my aim to so construct the laminated core members as to minimize the losses in the transformer by entirely avoiding air gaps in the reduced sections referred to.

In order to illustrate my improvement more fully, a substantially rectangular core member may be considered. Assuming that the structure is built up in the usual way, by assembling a plurality of L-shaped plates or punchings, the complete structure may be considered comprising a plurality of magnetic circuits in parallel, each of which contains two air-gaps. The importance of arranging these air gaps in any special manner, except for mechanical convenience, has not heretofore been appreciated. It, will, of course, be understood that, in core members of uniform cross-section, the? location of these air gaps would have no effect, provided the plates are thoroughlv interleaved in order to produce a solid and compact structure. On the other hand, when a portion of the core member is reduced in cross section, the effect produced by a favorable arrangement of the 'punchings is very marked. For example, I have found that, in a system of distribution having a large lighting or other peak load,; the line losses may be materially reduced and the all-day efliciency of the system improved by using transformers in which the punchings ment of the air-gap between the laminae in the same plane.

Referring to the drawings, the structure illustrated comprises a plurality of transformer core members l, 2, 3 and 4: and coils 5 and 6. The core members 2 and elare similar to each other and are cash provided with side portions 7, the cross-section of which is materially less than; that of the re maining side and ends; The two" sides 7 abut against each other and two corresponding sides of-the core'members l and 3'abut against the sides of the first two, as illustrated in Fig. '2 of the drawings. By this means, themean length of turn in the coils 5 and 6 is materially reduced and the expense of the transformer correspondingly diminished.

Referring to Fig. 8, the core member, as here shown, is built up of a plurality er L- shaped plates or punchings 8 and 9 which are interleaved in a well known manner to produce a substantial core structure. The L- shaped punchings 9 are each provided with arms 10 and 11 of unequal width, the arm 11 being equal in length to the longest dimension. of the structure and forming the portion of the completed core having the reduced cross-sectional area. The arms of the punching 8 are equal in widtlr and its ends abut against the inner edges of the punching 9 so that= the air-gaps formed between the two always lie in those portions of the core which have the full cross-sectional area, the arrangement of parts being such that it is impossible for any of the airgaps to lie in the reduced core portion.

It, is obviously immaterial whether the arm; 10 of the punching 9 is made equal in length to the full width of the core or whether or not its end abuts against the inner edge of the punching 8, so long as the proper relation exists between the arm 9 and the shorter arm of the pnnching 8 to insure a proper location of the air-gap, as-indieated above.

I claim. as my invention:

1. A magnetizable core having an eccentric coil-receiving opening and composed of layers each comprising a plurality of sections one of which has a relatively narrow side limb that extends the full length of the core.

2. A magnetizable core having an eccentric coil-receiving opening and composed of layers each of which comprises two unlike sections that make substantially equi-length butt joints with each other, one of said sections having a relatively narrow limb that extends the full length of the core.

3. A magnetizable core composed of multi-section layers and having an eccentric coil-receiving opening, onesection ofeach layer having a relatively narrow limb against the inner edge of which abuts the relatively side end of an adj acent section. I

In testimony whereof, I have hereunto subscribed my name this 10th day of November, 1908.

CHARLES LE G. FORTESCUE.

Witnesses: I

7. M. MoCoNAHEY, BIRNEY HINES. 

